A reading control technique is a technique of reading a digital stream recorded on a recording medium such as a BD-ROM at a desired rate, for example, at 4 times or 8 times, and supplying the read digital stream to a decoder.
Generally, a program for realizing this control is stored in a playback device as a built-in program. However, such a control program which is recorded on a BD-ROM and supplied to a playback device will become widespread in a near future, in order to produce a movie with a video stream being played back in conjunction with an application. The producing of the movie work will be described below.
When producing the movie work, an application using video data is recorded on a recording medium having the video data recorded thereon. Upon start-up by a playback device, the application sets a character in motion next to the video data being played on a screen. By making such an application to apply to a game or a quiz, an added value of the movie work will be enhanced greatly.
In such interactive control, adjustment of a video playback rate by the control program on the BD-ROM can speed up or slow down the motion of the character while playing back the video. By recording this control program on the BD-ROM for playback in the playback device, an interactive application in close conjunction with video can be distributed. As a result, the added value of the movie work can be further enhanced. Conventional techniques relating to adjustment of a playback rate include a known technology disclosed in the following Patent Document 1.    Patent Document 1: Japanese Patent Application Publication No. 2003-7035